An important factor for consideration in the flight of a lighter-than-air airship is its reliance on ballast to maintain flight at a selected flight level. Also, the ability of the airship to climb and descend is dependent on the control of the airship's ballast. It also happens that as the duration of flight is increased, the consequent increase in fuel burn exacerbates the ability to control the airship's ballast. In sum, the loss of fuel during an extended flight, without any ballast correction, can significantly increase the difficulty of descent, the landing of the airship, and the safe handling of the airship by a ground crew.
As is well known, the combustion of fuel in an air-breathing, reciprocating engine is accompanied by a marked increase in the temperature of the air that is mixed with the fuel for combustion. It is also well known that as air is cooled, water vapors in the air are condensed, and are removed from the air as liquid water. On this point, data is available which indicates that the weight of water that can be condensed from the exhaust gases of an air-breathing, reciprocating engine can equal, or even exceed, the weight of fuel that is burned.
Propeller theory clearly indicates that as a propeller is rotated, it draws air with increased velocity into the plane of the propeller rotation. The velocity of the air is then further increased as it passes through the propeller. At the same time, vortices are created at the tip of each propeller blade. The combined effect of all this is that air is moved with an increased velocity within a determinable distance beyond the tip of the propeller's rotating blades. From a thermodynamic perspective, it is also known that increased airflow velocities, such as are induced by a propeller rotation, can be used to enhance the cooling effect of an air mass.
In light of the above it is an object of the present invention to provide a system and method for maintaining the ballast of an engine-driven, lighter-than-air airship that uses condensed water from engine exhaust gases for ballast. Another object of the present invention is to provide a system and method for maintaining the ballast of an airship that employs the increase in airflow around and through a rotating, engine-driven propeller to enhance water condensation from engine exhaust gases. Still another object of the present invention is to provide a system and method for maintaining the ballast of an airship that is simple to use, relatively easy to manufacture, and comparatively cost effective.